Such gas bag restraint modules are known to the expert involved with vehicle passenger safety systems. Normally, a so-called gas generator having a pyrotechnical charge is used as the inflator, said pyrotechnical charge releasing a predetermined volume of gas in a very short time once activated. Recently, however, increased efforts have been made to develop gas bag restraint modules which operate with a much smaller pyrotechnical charge because the use of such pyrotechnical charges is not without problems, particularly in respect of environmental compatibility. The invention provides a gas bag restraint module of the type mentioned at the outset, which is adapted to use an inflator which has a pressurized gas container, in particular of the "heated gas inflator" type. With this type of inflator, a predetermined volume of gas is released to inflate the gas bag, said gas having been enclosed under high pressure in the pressurized gas cylinder. Upon activation of the inflator, a chemical reaction with the gas contained in the pressurized gas container is also initiated, whereby the temperature of the released gas is increased, thus leading to a corresponding increase in its volume.